Metal-Organic Framework Enabling Poly(Vinylidene Fluoride)-Based Polymer Electrolyte for Dendrite-Free and Long-Lifespan Sodium Metal Batteries

Sodium dentrite formed by uneven plating/stripping can reduce the utilization of active sodium with poor cyclic stability and, more importantly, cause internal short circuit and lead to thermal runaway and fire. Therefore, sodium dendrites and their related problems seriously hinder the practical application of sodium metal batteries (SMBs). Herein, a design concept for the incorporation of metal-organic framework (MOF) in polymer matrix (polyvinylidene fluoride-hexafluoropropylene) is practiced to prepare a novel gel polymer electrolyte (PH@MOF polymer-based electrolyte [GPE]) and thus to achieve high-performance SMBs. The addition of the MOF particles can not only reduce the movement hindrance of polymer chains to promote the transfer of Na+ but also anchor anions by virtue of their negative charge to reduce polarization during electrochemical reaction. A stable cycling performance with tiny overpotential for over 800 h at a current density of 5 mA cm(-2) with areal capacity of 5 mA h cm(-2) is achieved by symmetric cells based on the resulted GPE while the Na3V2O2(PO4)(2)F@rGO (NVOPF)|PH@MOF|Na cell also displays impressive specific cycling capacity (113.3 mA h g(-1) at 1 C) and rate capability with considerable capacity retention.

Automated summary

In this study, a novel gel polymer electrolyte (PH@MOF polymer-based electrolyte [GPE]) was prepared by incorporating metal-organic framework (MOF) particles in a polymer matrix (polyvinylidene fluoride-hexafluoropropylene) to achieve high-performance sodium metal batteries (SMBs). The addition of MOF particles not only promoted the transfer of Na+ by reducing the movement hindrance of polymer chains, but also reduced polarization during electrochemical reactions by anchoring anions with their negative charge. The resulted GPE showed stable cycling performance with tiny overpotential for over 800 hours at a current density of 5 mA cm(-2), and the NVOPF|PH@MOF|Na cell exhibited impressive specific cycling capacity (113.3 mA h g(-1) at 1 C) and rate capability with considerable capacity retention.